Carrier route record
UAPDX→DEN
United Airlines · Portland to Denver
- Flights
- 1,820
- Period
- July 2025 to June 2026
- Share of route
- 42%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on PDX to DEN earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 13 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 1,820 flights. The strongest carrier on the route with a full sample, Alaska Airlines, flew 582 at 76.8% on time.
Set against the rest of the country, United's PDX to DEN record is 13 points better than the US average of 77.6%. That gap is worth roughly 126 fewer late arrivals for every thousand flights.
Key figures
On time
90.2%
Arrivals under 15 minutes late, of 1,800 completed flights
Avg delay
71 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.81%
Whole route
80.8%
Every carrier on PDX to DEN, 4,290 flights
These figures cover 1,820 flights between July 2025 and June 2026. The median arrival is 11 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
United against every carrier on PDX to DEN
United flew 1,820 of the 4,290 flights on PDX to DEN, about 42% of it. Its 90.2% on time is 9 points better than the route as a whole, which runs 80.8%. Ranked by on-time rate it is first of five carriers on the route, where the range runs from United at 90.2% to SkyWest at 69.2%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 1,820 | 90.2% | 71 min | 0.55% | A+ |
| Frontier Airlinesthin sample | 312 | 77.3% | 61 min | 0.96% | B+ |
| Alaska Airlines | 582 | 76.8% | 52 min | 0.34% | B+ |
| Southwest Airlines | 1,563 | 72.2% | 49 min | 0.26% | C+ |
| SkyWest Airlinesthin sample | 13 | 69.2% | 39 min | 0.00% | C+ |
No carrier stands out. Alaska tops the table at 76.8%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
United flight numbers on PDX to DEN
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 15 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am347 flights97.1%
- 8am–11am396 flights96.4%
- 11am–2pm491 flights87.2%
- 2pm–5pm359 flights81.9%
- 5pm–8pm225 flights87.5%
- 8pm–5am2 flights—
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 97.1% of the time, against 81.9% for the afternoon window. That is 15 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 491 flights scheduled in it.
Across the year
United on PDX to DEN through the year
July is the worst month at 78.1% on time, 20 points below November, the best at 97.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. August was the busiest month here, with 177 flights.
Across the week, Sunday is the strongest day at 93.0% on time and Wednesday the weakest at 88.1%. 5 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 13,000 reported delay minutes.
- 38%Late-arriving aircraft
- 32%National Airspace System
- 29%Carrier
- 1%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 13,000 reported delay minutes here, that single category outweighs weather by 27 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 12,580 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 97.1% on time here.
Cancellations are rare at 0.55%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 3.5% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 991 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 81.7% on time across 1,821 flights, 9 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 9 points of difference.
The sample behind these figures is 1,820 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking United on PDX to DEN
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 97.8% on time and July 78.1%, a swing of 20 points. If the dates move at all, move them out of July before you think about anything else. 1,800 completed flights over 12 months sit behind that.
Related
Where to go next
- PDX to DEN, every carrier
- United on DEN to PDX, the return leg
- Frontier Airlines on PDX to DEN77.3%
- Alaska Airlines on PDX to DEN76.8%
- Southwest Airlines on PDX to DEN72.2%
- United Airlines network-wide record
- Portland International (PDX) delay statistics
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.